Serotype and genotype diversity of dengue viruses circulating in India: a multi-centre retrospective study involving the Virus Research Diagnostic Laboratory Network in 2018

Clinical characteristics and serotype association of dengue and dengue like illness in Pakistan

BACKGROUND

Pakistan has been an endemic country for dengue virus since 1994, with a significant increase in cases reported in 2022 largely due to heavy rainfall and flooding. All four serotypes of the dengue virus (DENV) are present in Pakistan, with DENV 1 and DENV 2 being the most prevalent. The current study aims to explore the clinical presentations and features of dengue fever in a tertiary care hospital.

METHODOLOGY

We enrolled and studied 349 cases of suspected and confirmed dengue presenting for care at the Aga Khan University Hospital in Karachi between June 2021 and November 2023. Collected data on cases included clinical symptoms and laboratory results including qRT-PCR and serotype characterization.

FINDINGS

The majority of subjects enrolled (75%) had mild disease without warning signs, while 11% exhibited warning signs, 1.4% had severe dengue, and 12.6% had no dengue diagnosis. Patients with severe dengue (SD) had significantly higher levels of liver enzymes (AST and ALT) compared to those with non-severe dengue (NSD) (AST; p = 0.024 and ALT; p = 0.047). Additionally, a higher grade of thrombocytopenia was significantly associated with hospitalization (p = 0.0008), and prolonged illness (p = 0.03). Both Platelet (p < 0.0001) and WBC counts (p = 0.001) were significantly lower in dengue PCR-positive patients in comparison to Dengue PCR-negative. Among those tested for dengue serotypes, DENV 1 (34%) and DENV 2 (45%) emerged as the predominant serotypes, with mixed infections accounting for 17%. The sensitivity of q-RT PCR was found to be 87.25% and the specificity of 68.35%. qRT-PCR detected 43.5% of cases with viral fever initially screened negative by IgM or NS1.

CONCLUSION

The epidemiology of dengue fever during a widespread outbreak in 2022 showed a predominance of DENV 1 and DENV 2 serotypes with milder phenotype of viral illness. Screening with rapid tests requires further confirmation by molecular assay in cases with dengue and dengue-like illness. The sensitivity of q-RT PCR using gold standard.

Epidemiological and molecular typing of dengue viruses circulating in Jorhat district, Assam, India

BACKGROUND

Dengue is a significant mosquito-borne infection that causes public health concern, particularly in tropical and subtropical regions. This study aimed to characterize the molecular typing of dengue viruses in Jorhat district, as information on dengue serotypes is scarce in India.

METHODS

A total of 1359 serum samples of clinically suspected dengue cases were tested for non-structural protein 1 (NS1) antigen and Immunoglobulin M (IgM) antibody using enzyme-linked immunosorbent assay (ELISA). Additionally, viral RNA was extracted from positive samples for multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) to determine the dengue serotypes. Seasonal variations, gender, and age-wise incidences were also studied. Statistical analysis was performed to assess demographic and clinical characteristics.

RESULTS

This study depicts a substantial burden of dengue, with 370 (27.22 %) positive samples. IgM and NS1 ELISA tested positive for 42 (11.3 %) and 328 (88.6 %) samples. Dengue virus (DENV) cases predominantly affected males (58.4 %) and the age group of 16-30 years. The major clinical manifestations include fever, headache, and body aches. Serotyping revealed DENV-2 as the predominant serotype, followed by DENV-3 and DENV-1. The co-infection of DENV-2 and DENV-3 was observed in many cases. Seasonal clustering of dengue cases indicates the highest peak in September and October.

CONCLUSIONS

This study provides valuable insights into the epidemiology, diagnosis, and serotyping of dengue viruses in the Jorhat district of Assam, emphasizing the need for continued surveillance and effective vector control measures that should be implemented to mitigate the early detection of dengue in this region.

Serotype and genotype shift detection over two consecutive periods of dengue virus infection in a tertiary care hospital

PURPOSE

Dengue virus infection in humans can also lead to severe complications like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The World Health Organization (WHO) estimates around 50 to 100 million dengue infections annually, with approximately 500,000 cases of DHF and 22,000 deaths, predominantly among children. The present study aimed at identifying circulating serotypes of dengue virus in patients by molecular techniques. Serotypes detected were correlated with the clinical profiles, complications, and outcomes in these patients.

METHODS

This study was conducted between October 2019 to September 2022. Institute Ethics Committee approval was obtained (Reference no. IEC: RC/18/59). Serum from patients who tested positive for dengue NS1 antigen (NS1Ag) or anti-dengue immunoglobulin M (IgM) were serotyped by dengue reverse transcriptase polymerase chain reaction (RT-PCR). Clinical data was documented in case report forms and transferred to an Excel spreadsheet, and subsequently analyzed to correlate the dengue virus (DENV) serotype with clinical profile and outcome.

RESULTS

The study population included 416 patients, confirmed by Dengue NS1Ag and or anti-Dengue IgM ELISA. Young adults (18-29 yrs) constituted the majority (56 %) of patients. About 85 % of all patients presented with fever, 10.6 % with hemorrhagic fever, and 4.4 % with shock syndrome. Thrombocytopenia with multiple bleeding manifestations was observed in 6.5 % of the patients. The predominant dengue serotype identified was serotype 3 from October 2019 to March 2021, and serotype 2 from April 2021 to September 2022, showing a shift in the serotypes affecting the patients.

CONCLUSION

Continuous sero- and molecular surveillance plays a crucial role in predicting dengue outbreaks and identifying shifts in circulating serotypes during the early phase of the dengue season. It may also play a role in vaccine preparedness for the control of dengue.

Severity prediction markers in dengue: a prospective cohort study using machine learning approach

BACKGROUND

Dengue virus causes illnesses with or without warning indicators for severe complications. There are no clear prognostic signs linked to the disease outcomes.

METHODS

Clinical and laboratory parameters among 102 adult including 17 severe dengue (SD), 33 with warning and 52 without warning signs during early and critical phases were analysed by statistical and machine learning (ML) models.

RESULTS

In classical statistics, abnormal ultrasound findings, platelet count and low lymphocytes were significantly linked with SD during the febrile phase, while low creatinine, high sodium and elevated AST/ALT during the critical phase. ML models highlighted AST/ALT and lymphocytes as key markers for distinguishing SD from non-severe dengue, aiding clinical decisions.

CONCLUSION

Parameters like liver enzymes, platelet counts and USG findings were linked with SD.USG testing at an earlier phase of dengue and a point-of-care system for the quantification of AST/ALT levels may lead to an early prediction of SD.

Dengue epidemiology and molecular characterization of vector mosquitoes; Aedes aegypti and Aedes albopictus in Mizoram, Northeast India

BACKGROUND

Dengue is the most important arboviral disease, and Aedes aegypti and Aedes albopictus are the major vectors. It is one of the most recent emerging diseases in Mizoram state with a fast-growing burden over the years. The present study aimed to explore the epidemiological patterns of dengue in Mizoram, and to identify vector mosquito species.

METHODS

In the present study, two years secondary data of dengue disease in Mizoram was studied. Dengue vector mosquitoes and dengue virus serotypes circulating in vector mosquitoes in Aizawl City were identified by sequence analysis of COX1 and C-prM genes respectively.

RESULTS

In Mizoram State, the annual case prevalence of dengue was found to be 300.45 per 100,000 persons. Seasonality of the disease was also noted, with the peak season occurring from July to December. There is a significant positive relationship between age and the disease prevalence (p < 0.05, r = 0.909). DENV was detected in 10 pools of Ae. aegypti with a minimum infection rate (MIR) of 18.05, and 8 pools of Ae. albopictus with a minimum infection rate of 16.03. The viral isolates were found to correspond to serotypes 2 (DENV2) and 3 (DENV3). A total of 6 pools of Aedes aegypti and 4 pools of Aedes albopictus tested positive with DENV2 serotype, while 4 pools of Aedes aegypti and 3 pools of Aedes albopictus tested positive with DENV3 serotype. DENV2 serotype was more common, and multiple serotypes (DENV2 and DENV3) were also detected in two pools from one locality.

CONCLUSIONS

There is an increasing trend in dengue infection in Mizoram, and seasonality of the disease was observed with the peak season during July to December. The higher incidence rate among the adults indicated that outdoor activities may be related to the high risk of the infection. However, lack of immunity among the older people may also be a possible reason of higher disease incidence rather than the activity pattern. Early identification and frequent monitoring of infected vector mosquitoes will yield an early warning indicator for forecasting dengue epidemics in the future.

Diagnostics for optimised dengue surveillance: a qualitative focus group study to investigate user experience and requirements in Thailand

OBJECTIVES

Effective, real-time surveillance of dengue may provide early warning of outbreaks and support targeted disease-control intervention but requires widespread accurate diagnosis and timely case reporting. Research directing innovation in diagnostics for dengue surveillance is lacking. This study aimed to describe experience and requirements of relevant prospective users.

DESIGN

A qualitative, focus group study was conducted.

PARTICIPANTS

Data were collected from 19 users of diagnostic technology who work across the Thai dengue surveillance system.

DATA COLLECTION AND ANALYSIS

Contextual knowledge, experience and needs were explored in focus groups. Discussions were translated, transcribed, analysed thematically and mapped to Consolidated Framework for Implementation Research domains.

RESULTS

Participants expressed a need for rapid, accurate, serotype-specific tests which can be operated easily by non-expert users without laboratory equipment. They supported integration of diagnostics with surveillance systems and felt this would increase the quantity and speed of case reporting as well as provide healthcare professionals with up-to-date information about the number of cases locally, thereby aiding interpretation of test results. Concerns included those relating to data security and the cost of tests.

CONCLUSIONS

Engagement to understand prospective user experience and requirements can improve relevance and uptake of new technology, leading to system efficiencies. The present study highlights specific needs for accurate, serotype-specific, remote-connected diagnostics which are integrated with surveillance systems and support dengue case reporting at the point-of-care.

Trends in dengue virus positivity & serotyping in Rajasthan

Background & objectives Dengue virus causes frequent outbreaks and epidemics with high morbidity and mortality. It is important to monitor the trends of the dengue virus and its serotypes. We carried out the present work to study the prevalence of the dengue virus and its serotypes in clinically suspected cases of dengue in Rajasthan. Methods A total of 1,47,777 individuals reporting as pyrexia of unknown origin or clinically suspected of dengue infection were included in this study. The presence of dengue NS1 antigen and dengue IgM was tested by ELISA. Nucleic acid extraction and PCR was done for detection of dengue virus RNA. Serotyping of representative dengue PCR-positive samples was done by real time PCR. Results Of the 1,47,777 dengue suspected cases, 28092 (19.01%) were positive for dengue by NS1antigen or IgM ELISA. Year-wise percentage positivity from 2015 to 2022 was 30.42, 16.49, 17.81, 20.15, 20.50, 9.25, 24.55 and 15.16 per cent, respectively. Males of age >15 yr were found to be more commonly affected. The number of dengue cases was significantly higher during the post-monsoon period throughout the eight-year study period. All four dengue serotypes circulated during the study period. DENV-2 and DENV-3 were the predominant serotypes during 2015 to 2017, while DENV-1 and DENV-2 were predominant during 2018 to 2022. Interpretation & conclusion The findings of this study suggest that the dengue positivity in Rajasthan was the highest in post-monsoon season among adult males. The serotype prevalent varied from time to time and was helpful in understanding the changing epidemiology of DENV.

Dengue in Pune city, India (2017-2019): a comprehensive analysis

Objectives

To understand the dynamics of dengue disease with special reference to (1) age (2) primary/secondary infections (3) serostatus and (4) serotypes examined during three consecutive years.

Methods

During 3 dengue seasons (2017-19), NS1/IgM ELISAs were used for dengue diagnosis in one of the 15 administrative wards of Pune City, India. Predefined symptoms were recorded at the time of diagnosis/hospitalization. IgG-capture ELISA (Panbio) was used to differentiate primary/secondary infections. DENV serotypes were determined for 260 viral RNA-positive patients.

Results

During the 3 years, 3,014/6,786 (44.4%, 41.4-49.9%) suspected cases were diagnosed as dengue. Use of either NS1 or IgM would have missed 25.5% or 43% of the confirmed dengue cases, respectively. Notably, a higher proportion of secondary dengue cases remained mild while a substantial proportion of primary infections developed warning signs. The symptoms among Dengue/non-dengue patients and primary/secondary infections varied and influenced by age and serostatus. The number and proportion of dengue serotypes varied yearly. A remarkable decline in dengue cases was observed during the COVID-19 pandemic years.

Conclusion

A substantial proportion of primary and secondary dengue patients progress to warning signs/severity or mild infection respectively, underscoring the possible role of non-ADE mechanisms in causing severe dengue that requires hospitalization. Both NS1 and IgM should be used for efficient diagnosis.

Regional Variation of the CD4 and CD8 T Cell Epitopes Conserved in Circulating Dengue Viruses and Shared with Potential Vaccine Candidates

As dengue expands globally and many vaccines are under trials, there is a growing recognition of the need for assessing T cell immunity in addition to assessing the functions of neutralizing antibodies during these endeavors. While several dengue-specific experimentally validated T cell epitopes are known, less is understood about which of these epitopes are conserved among circulating dengue viruses and also shared by potential vaccine candidates. As India emerges as the epicenter of the dengue disease burden and vaccine trials commence in this region, we have here aligned known dengue specific T cell epitopes, reported from other parts of the world with published polyprotein sequences of 107 dengue virus isolates available from India. Of the 1305 CD4 and 584 CD8 epitopes, we found that 24% and 41%, respectively, were conserved universally, whereas 27% and 13% were absent in any viral isolates. With these data, we catalogued epitopes conserved in circulating dengue viruses from India and matched them with each of the six vaccine candidates under consideration (TV003, TDEN, DPIV, CYD-TDV, DENVax and TVDV). Similar analyses with viruses from Thailand, Brazil and Mexico revealed regional overlaps and variations in these patterns. Thus, our study provides detailed and nuanced insights into regional variation that should be considered for itemization of T cell responses during dengue natural infection and vaccine design, testing and evaluation.

Safety and durable immunogenicity of the TV005 tetravalent dengue vaccine, across serotypes and age groups, in dengue-endemic Bangladesh: a randomised, controlled trial

BACKGROUND

Morbidity and mortality from dengue virus (DENV) is rapidly growing in the large populations of south Asia. Few formal evaluations of candidate dengue vaccine candidates have been undertaken in India, Pakistan, or Bangladesh. Tetravalent vaccines must be tested for safety and immunogenicity in all age groups and in those previously exposed and naive to DENV infections. TV005 is a live, attenuated tetravalent dengue vaccine. We evaluated the safety and immunogenicity of a single dose of TV005 across age groups in dengue-endemic Bangladesh.

METHODS

We performed a randomised, placebo-controlled age de-escalating clinical trial of TV005 at a single clinical site in dengue-endemic Dhaka, Bangladesh, following a technology transfer from the USA. Healthy (as determined by history, clinical examination, and safety laboratory test results) volunteers aged 1-50 years were randomly assigned 3:1 (stratified by four age groups) to receive a single dose of TV005 vaccine or placebo. Participants were followed up for 3 years. The study was double blind and was unmasked at day 180; outcome assessors, clinic staff, and volunteers remained blind throughout. Primary outcomes were safety, evaluated per-protocol as proportion of volunteers with solicited related adverse events of any severity through 28 days post dosing, and post-vaccination seropositivity by day 180 using serotype-specific neutralising antibodies (PRNT50 ≥10). Secondary outcomes included viremia, impact of past dengue exposure, and durability of antibody responses. This study is registered with Clinicaltrials.gov, NCT02678455, and is complete.

FINDINGS

Between March 13, 2016, and Feb 14, 2017, 192 volunteers were enrolled into four age groups (adults [18-50 years; 20 male and 28 female], adolescents [11-17 years; 27 male and 21 female], children [5-10 years; 15 male and 33 female], and young children [1-4 years; 29 male and 19 female]) with 48 participant per group. All participants were Bangladeshi. Vaccination was well tolerated and most adverse events were mild. Rash was the most common vaccine-associated solicited adverse event, in 37 (26%) of 144 vaccine recipients versus six (12%) of 48 placebo recipients; followed by fever in seven (5% of 144) and arthralgias in seven (6% of 108), which were only observed in vaccine recipients. Post-vaccine, volunteers of all ages (n=142) were seropositive to most serotypes with 118 (83%) seropositive to DENV 1, 141 (99%) to DENV 2, 137 (96%) to DENV 3, and 124 (87%) to DENV 4, overall by day 180. Post-vaccination, viraemia was not consistently found and antibody titres were higher (10-15-fold for DENV 1-3 and 1·6-fold for DENV 4) in individuals with past dengue exposure compared with the dengue-naive participants (DENV 1 mean 480 [SD 4·0] vs 32 [2·4], DENV 2 1042 [3·2] vs 105 [3·1], DENV 3 1406 [2·8] vs 129 [4·7], and DENV 4 105 [3·3] vs 65 [3·1], respectively). Antibody titres to all serotypes remained stable in most adults (63-86%) after 3 years of follow-up. However, as expected for individuals without past exposure to dengue, titres for DENV 1, 3, and 4 waned by 3 years in the youngest (1-4 year old) cohort (69% seropositive for DENV 2 and 22-28% seropositive for DENV 1, 3, and 4).

INTERPRETATION

With 3 years of follow-up, the single-dose tetravalent dengue vaccine, TV005, was well tolerated and immunogenic for all four serotypes in young children to adults, including individuals with no previous dengue exposure.

FUNDING

National Institutes of Health-National Institute of Allergy and Infectious Diseases Intramural Research Program and Johns Hopkins University.

TRANSLATION

For the Bangla translation of the abstract see Supplementary Materials section.

The Spatiotemporal Distribution and Molecular Characterization of Circulating Dengue Virus Serotypes/Genotypes in Senegal from 2019 to 2023

Dengue virus is becoming a major public health threat worldwide, principally in Africa. From 2016 to 2020, 23 outbreaks were reported in Africa, principally in West Africa. In Senegal, dengue outbreaks have been reported yearly since 2017. Data about the circulating serotypes and their spatial and temporal distribution were limited to outbreaks that occurred between 2017 and 2018. Herein, we describe up-to-date molecular surveillance of circulating DENV serotypes in Senegal between 2019 to 2023 and their temporal and spatial distribution around the country. For this purpose, suspected DENV-positive samples were collected and subjected to dengue detection and serotyping using RT-qPCR methods. Positive samples were used for temporal and spatial mapping. A subset of DENV+ samples were then sequenced and subjected to phylogenetic analysis. Results show a co-circulation of three DENV serotypes with an overall predominance of DENV-3. In terms of abundance, DENV-3 is followed by DENV-1, with scarce cases of DENV-2 from February 2019 to February 2022. Interestingly, data show the extinction of both serotype 1 and serotype 2 and the only circulation of DENV-3 from March 2022 to February 2023. At the genotype level, the analysis shows that sequenced strains belong to same genotype as previously described: Senegalese DENV-1 strains belong to genotype V, DENV-2 strains to the cosmopolitan genotype, and DENV-3 strains to Genotype III. Interestingly, newly obtained DENV 1-3 sequences clustered in different clades within genotypes. This co-circulation of strains belonging to different clades could have an effect on virus epidemiology and transmission dynamics. Overall, our results highlight DENV serotype replacement by DENV-3, accompanied by a wider geographic distribution, in Senegal. These results highlight the importance of virus genomic surveillance and call for further viral fitness studies using both in vitro and in vivo models, as well as in-depth phylogeographic studies to uncover the virus dispersal patterns across the country.

Circulating serotypes and genotypes of dengue virus in North India: An observational study

BACKGROUND OBJECTIVES

This study reports observation on circulating serotypes and genotypes of Dengue Virus in North India.

METHODS

Serum samples were obtained from suspected cases of dengue referred to the virus diagnostic laboratory during 2014 to 2022. All samples were tested for anti-dengue virus IgM antibodies and NS1Ag by ELISA. NS1Ag positive samples were processed for serotyping and genotyping.

RESULTS

Total 41,476 dengue suspected cases were referred to the laboratory of which 12,292 (29.6%) tested positive. Anti-Dengue Virus IgM antibodies, NS1Ag, both IgM and NS1Ag, were positive in 7007 (57.4%); 3200 (26.0%) and 2085 (16.0%) cases respectively. Total 762 strains were serotyped during 9-year period. DENV-1, DENV-2, DENV-3 and DENV-4 serotypes were found in 79 (10.37%), 506 (66.40%), 151 (19.82%) and 26 (3.41%) cases respectively. DENV-1, DENV-2 and DENV-3 were in circulation throughout. Total 105 strains were genotyped. Genotype IV of DENV-1 serotype was circulating till 2014 which was later replaced by genotype V. A distinct seasonality with increase in number of cases in post-monsoon period was seen.

INTERPRETATION CONCLUSION

DENV-1, DENV-2 and DENV-3 were found to be in circulation in North India. Predominant serotype/genotype changed at times, but not at regular intervals.

Synthesis of novel rhodamine type Anthrone Spiro-lactam (ASL) analogues and evaluation of antiviral activity against dengue and chikungunya viruses

A series of Rhodamine type Anthrone-Spirolactam (ASL) derivatives Benzylimin-Anthrone-Spirolactam (ASL-1 to ASL-10) and Benzamide-Anthrone-Spirolactam (ASL-11 and ASL-12) were synthesized via a simple condensation reaction between Anthrone Spiro-lactamine (2) and various aromatic aldehyde and acyl chlorides respectively. Since rhodamine-based compounds were reported to have antiviral activity, the ASL derivatives were examined for in vitro antiviral activity against dengue and chikungunya viruses. Among all the analogues, ASL-3, ASL-6, ASL-7, ASL-8, ASL-9 and ASL-10 were the most potent against dengue virus (DENV) and exerted around one log reduction in virus titre under post-treatment conditions. At the same time ASL-3 was effective under co-treatment conditions. Two analogues ASL-6 and ASL-12 exerted anti-chikungunya virus (CHIKV) activity under post-treatment conditions. In silico docking studies revealed that the ASL derivatives interacted with the proteins of DENV and CHIKV. Together, the results suggest the anti-DENV and CHIKV activity of ASL derivatives which may be exploited further for therapeutic purposes.

Changing pattern of circulating dengue serotypes in the endemic region: An alarming risk to the healthcare system during the pandemic

BACKGROUND

The pandemic of COVID-19 has created an unprecedented burden on the healthcare system and medical communities resulting in new public health challenges. On the other hand, in tropical countries, another concern arises due to the similar spectrum of clinical manifestations between COVID-19 and dengue fever. Thus, the neglected tropical disease 'Dengue' writhed with more inattention. This study aims to find the effect of the COVID-19 pandemic on dengue infections in endemic areas of West Bengal, India, and their combined impact on public health. The alterations in circulating dengue serotype and their genomic diversity in different COVID-19 waves were also monitored.

METHODS

A total of 1782 patients were included in this study. Dengue NS1 ELISA, molecular serotyping, genotyping and their phylogenetic analysis were performed. GISaided analysis of various dengue serotypes and hotspot identification for risk maps of severe dengue in endemic zones were done. The burden of dengue fever and the sustainability of their viral strains with changing meteorological parameters in parallel to COVID-19 waves were analyzed.

RESULTS

Co-circulation of all the four dengue serotypes with rapid change in the pattern of prevalent serotype DENV4 (Genotype-I) in the year 2020 and DENV3 (Genotype-III) in 2021 were observed, in parallel to different circulating strains of COVID-19. Spatiotemporal distribution of DENV using Geographic Information System (GIS) applications observed a serotypic shift and hotspot mapping for risk analysis detected Kolkata as a dengue hotspot, which has also reported the maximum number of COVID-19 cases.

CONCLUSION

This study indicates the increased fitness of circulating dengue virus strains with optimal virulence as per changing environmental conditions and the inhabitant's immunity. The high infectivity rate of both the RNA viruses and considering.the consequences of severe dengue and COVID-19 in the population of the same geographical settings is an alarming risk.

Seroprevalence of dengue virus infection in Pune City in India, 2019: A decadal change

BACKGROUND

The burden of dengue infection needs to be monitored along with tracking of the changes in dengue virus (DENV) transmission intensity for vaccine introduction decisions.

METHODS

The seroprevalence of dengue was investigated in Pune City in India, in early 2019 using 1654 sera from apparently healthy human participants enrolled randomly through multistage cluster sampling. We used 797 retrospective human sera from late 2009 for comparison. All sera were assessed for the presence of dengue-specific IgG antibodies. A subset (n = 230) was tested for serotype-specific plaque reduction-neutralizing antibodies against all four serotypes.

RESULTS

The dengue IgG seroprevalence of 62.9% (95% CI 59.4-66.1) in 2009 increased to 88.4% (95% CI 86.8-89.8) in 2019. Age-stratified dengue seroprevalence revealed a gradual increase in IgG seropositivity from 70.1% in 0-9 years to 85.0% in 10-19 years. The annual probability of dengue infection estimated as a force of infection was 4.1 (95% CI 3.8-4.5) in 2009, which increased to 10.9 (95% CI 10.2-11.6) in 2019. Analysis of dengue serotype-specific neutralizing antibodies revealed DENV-3 as the dominant serotype. The age of exposure to at least one dengue serotype was reduced in 2019 over 2009.

CONCLUSIONS

There was a significant increase in the intensity of dengue virus transmission in Pune City over the decade. Since over 85% of the participants above nine years of age had exposure to DENV by 2019, dengue vaccine introduction can be considered. Moreover, such repeated serosurveys in different regions might inform about the readiness of the population for dengue vaccination.

Molecular surveillance of dengue virus in field-collected Aedes mosquitoes from Bhopal, central India: evidence of circulation of a new lineage of serotype 2

Introduction

Dengue fever is hyperendemic in several Southeast and South Asian countries, including India, with all four serotypes (DENV 1-4) circulating at different periods and in different locations. Sustainable and improved virological and entomological surveillance is the only tool to prevent dengue and other vector-borne diseases.

Objectives

The present study has been carried out to detect and characterize the circulating dengue virus (DENV) in field-collected Aedes mosquitoes in Bhopal, Central India.

Methods

Aedes mosquitoes were collected from 29 localities within Bhopal city during October 2020 to September 2022. DENV infection was assessed in the individual head and thorax regions of Aedes mosquitoes using reverse transcriptase PCR. Positive samples were sequenced, and the circulating serotypes and genotypes were determined using phylogenetic analysis.

Results

DENV RNA was detected in 7 Aedes aegypti and 1 Aedes albopictus, with infection rates of 0.59 and 0.14%, respectively. Phylogenetic analysis revealed all the isolates belonged to DENV serotype 2 and distinctly clustered with the non-Indian lineage (cosmopolitan genotype 4a), which was not recorded from the study area earlier. The time to most common recent ancestor (TMRCA) of these sequences was 7.4 years old, with the highest posterior density (HPD) of 3.5-12.2 years, indicating that this new lineage emerged during the year 2014. This is the first report on the DENV incrimination in both Ae. aegypti and Ae. albopictus mosquitoes collected from Bhopal, Central India.

Conclusion

The observed emergence of the non-Indian lineage of DENV-2 in Bhopal, which again is a first report from the area, coincides with the gradual increase in DENV cases in Bhopal since 2014. This study emphasizes the importance of DENV surveillance and risk assessment in this strategically important part of the country to decipher its outbreak and severe disease-causing potential.

Genetic Analysis of Dengue Virus in Severe and Non-Severe Cases in Dhaka, Bangladesh, in 2018-2022

Dengue virus (DENV) infections have unpredictable clinical outcomes, ranging from asymptomatic or minor febrile illness to severe and fatal disease. The severity of dengue infection is at least partly related to the replacement of circulating DENV serotypes and/or genotypes. To describe clinical profiles of patients and the viral sequence diversity corresponding to non-severe and severe cases, we collected patient samples from 2018 to 2022 at Evercare Hospital Dhaka, Bangladesh. Serotyping of 495 cases and sequencing of 179 cases showed that the dominant serotype of DENV shifted from DENV2 in 2017 and 2018 to DENV3 in 2019. DENV3 persisted as the only representative serotype until 2022. Co-circulation of clades B and C of the DENV2 cosmopolitan genotype in 2017 was replaced by circulation of clade C alone in 2018 with all clones disappearing thereafter. DENV3 genotype I was first detected in 2017 and was the only genotype in circulation until 2022. We observed a high incidence of severe cases in 2019 when the DENV3 genotype I became the only virus in circulation. Phylogenetic analysis revealed clusters of severe cases in several different subclades of DENV3 genotype I. Thus, these serotype and genotype changes in DENV may explain the large dengue outbreaks and increased severity of the disease in 2019.

Dengue as a Disease Threatening Global Health: A Narrative Review Focusing on Latin America and Brazil

Arboviruses constitute the largest known group of viruses. These viruses are the etiological agents of pathologies known as arboviruses, with dengue being one of the most prevalent. Dengue has resulted in important socioeconomic burdens placed on different countries around the world, including those in Latin America, especially Brazil. Thus, this work intends to carry out a narrative-based review of the literature, conducted using a study of the secondary data developed through a survey of scientific literature databases, and to present the situation of dengue, particularly its distribution in these localities. Our findings from the literature demonstrate the difficulties that managers face in controlling the spread of and planning a response against dengue, pointing to the high cost of the disease for public coffers, rendering the resources that are already limited even scarcer. This can be associated with the different factors that affect the spread of the disease, including ecological, environmental, and social factors. Thus, in order to combat the disease, it is expected that targeted and properly coordinated public policies need to be adopted not only in specific localities, but also globally.

Cross-reactivity of SARS-CoV-2 with other pathogens, especially dengue virus: A historical perspective

Dengue is a vector-borne viral disease caused by a Flavivirus whereas the COVID-19 pandemic was caused by a highly contagious virus, SARS-CoV-2 belonging to the family Coronaviridae. However, COVID-19 severity was observably less in dengue-endemic countries and vice versa especially during the active years of the pandemic (2019-2021). We observed that dengue virus (DENV) antibodies (Abs) could cross-react with SARS-CoV-2 spike antigen. This resulted in SARS-CoV-2 false positivity by rapid Ab test kits. DENV Abs binding to SARS-CoV-2 receptor-binding domain (and the reverse scenario), as revealed by docking studies further validated DENV and SARS-CoV-2 cross-reactivity. Finally, SARS-CoV-2 Abs were found to cross-neutralize DENV1 and DENV2 in virus neutralization test (VNT). Abs to other pathogens like Plasmodium were also cross-reactive but non-neutralizing for SARS-CoV-2. Here, we analyze the existing data on SARS-CoV-2 cross-reactivity with other pathogens, especially dengue to assess its impact on health (cross-protection?) and differential sero-diagnosis/surveillance.

Co-circulation of all the four Dengue virus serotypes during 2018-2019: first report from Eastern Uttar Pradesh, India

Dengue fever is an endemic disease in India, transmitted by an infected mosquito bite. In India, the number of concurrent infections and the circulation of multiple dengue virus (DENV) serotypes has increased in recent decades. Molecular surveillance among the DENV serotype is important to keep track of the circulating serotypes, evolutionary changes, and key mutations that can alter the diagnostics. The current study included patients admitted for dengue in the Eastern Uttar Pradesh (E-UP) region during 2018-2019. The genetic characterization of the circulating DENV was accomplished through partial CprM (511 bp) gene amplification via reverse transcriptase polymerase chain reaction and sequencing. Phylogenetic analysis revealed the circulation of all four DENV1-4 serotypes. DENV-2 was the most abundant serotype (44%, 27/61), followed by DENV-3 (32%, 20/61). DENV-1 had a 16% (10/61) predominance, while DENV-4 (6%, 4/61) was found to be the least abundant serotype. DENV-2 genotypes were distributed among lineages I (7.4%), II (85%) and III (7.4%) of genotype IV, DENV-3 to lineage III of genotype III, DENV-1 to genotype III; DENV-2 to lineage B (75%) and C (25%) of genotype I. This primary report on the co-circulation of DENV1-4 serotypes from the E-UP region highlights the requirement of continuous molecular surveillance for monitoring circulating DENV serotypes.

Zika a Vector Borne Disease Detected in Newer States of India Amidst the COVID-19 Pandemic

Background

During the second wave of the COVID-19 pandemic, outbreaks of Zika were reported from Kerala, Uttar Pradesh, and Maharashtra, India in 2021. The Dengue and Chikungunya negative samples were retrospectively screened to determine the presence of the Zika virus from different geographical regions of India.

Methods

During May to October 2021, the clinical samples of 1475 patients, across 13 states and a union territory of India were screened and re-tested for Dengue, Chikungunya and Zika by CDC Trioplex Real time RT-PCR. The Zika rRTPCR positive samples were further screened with anti-Zika IgM and Plaque Reduction Neutralization Test. Next generation sequencing was used for further molecular characterization.

Results

The positivity was observed for Zika (67), Dengue (121), and Chikungunya (10) amongst screened cases. The co-infections of Dengue/Chikungunya, Dengue/Zika, and Dengue/Chikungunya/Zika were also observed. All Zika cases were symptomatic with fever (84%) and rash (78%) as major presenting symptoms. Of them, four patients had respiratory distress, one presented with seizures, and one with suspected microcephaly at birth. The Asian Lineage of Zika and all four serotypes of Dengue were found in circulation.

Conclusion

Our study indicates the spread of the Zika virus to several states of India and an urgent need to strengthen its surveillance.

Computational design of immunogenic peptide constructs comprising multiple HLA restricted Dengue virus envelope epitopes

Dengue virus (DENV) is endemic in 100 countries with ability to impact nearly 50% of world population. DENV envelope (E) protein is responsible for viral attachment to host cells and has been target of various countermeasure development efforts. The current study focuses on a consensus computational approach to identify cross-reactive, immunogenic DENV-2 E peptides displaying promiscuity with a wide array of HLA molecules. Four conserved peptides (FP-1, FP-2, FP-3 and FP-4) containing multiple CD8⁺ and CD4⁺ T cell epitopes were identified by employment of various immunoinformatics tools. FP-1, FP-2, FP-3 and FP-4 were estimated to bind with 227, 1787, 1008 and 834 HLA alleles respectively. RMSD values obtained by Molecular docking (CABS-Dock) with 20 HLA alleles (10 each of HLA class I and II) resulted into comparable RMSD values of identified epitopes with native peptides which represents the natural presentation of epitopes to HLA molecules. These peptides were also found to be part of previous experimentally validated immunogenic peptides. Further, a dengue immunogenic peptide construct was generated by linking the four peptides, an adjuvant and a 6x histidine tag. The construct showed strong binding and stability with Toll-like receptor (TLR4). Collectively, these results provide strong evidence in the support of the immunogenic potential of the dengue immunogenic peptide construct. This article is protected by copyright. All rights reserved.

Immune profile and responses of a novel dengue DNA vaccine encoding an EDIII-NS1 consensus design based on Indo-African sequences

The ongoing COVID-19 pandemic highlights the need to tackle viral variants, expand the number of antigens, and assess diverse delivery systems for vaccines against emerging viruses. In the present study, a DNA vaccine candidate was generated by combining in tandem envelope protein domain III (EDIII) of dengue virus serotypes 1-4 and a dengue virus (DENV)-2 non-structural protein 1 (NS1) protein-coding region. Each domain was designed as a serotype-specific consensus coding sequence derived from different genotypes based on the whole genome sequencing of clinical isolates in India and complemented with data from Africa. This sequence was further optimized for protein expression. In silico structural analysis of the EDIII consensus sequence revealed that epitopes are structurally conserved and immunogenic. The vaccination of mice with this construct induced pan-serotype neutralizing antibodies and antigen-specific T cell responses. Assaying intracellular interferon (IFN)-γ staining, immunoglobulin IgG2(a/c)/IgG1 ratios, and immune gene profiling suggests a strong Th1-dominant immune response. Finally, the passive transfer of immune sera protected AG129 mice challenged with a virulent, non-mouse-adapted DENV-2 strain. Our findings collectively suggest an alternative strategy for dengue vaccine design by offering a novel vaccine candidate with a possible broad-spectrum protection and a successful clinical translation either as a stand alone or in a mix and match strategy.

Traditional Knowledge to Contemporary Medication in the Treatment of Infectious Disease Dengue: A Review

Dengue has become a worldwide affliction despite incessant efforts to search for a cure for this long-lived disease. Optimistic consequences for dengue vaccine are implausible as the efficiency is tied to previous dengue virus (DENV) exposure and a very high cost is required for large-scale production of vaccine. Medicinal plants are idyllic substitutes to fight DENV infection since they constitute important components of traditional medicine and show antiviral properties, although the mechanism behind the action of bioactive compounds to obstruct viral replication is less explored and yet to be discovered. This review includes the existing traditional knowledge on how DENV infects and multiplies in the host cells, conscripting different medicinal plants that obtained bioactive compounds with anti-dengue properties, and the probable mechanism on how bioactive compounds modulate the host immune system during DENV infection. Moreover, different plant species having such bioactive compounds reported for anti-DENV efficiency should be validated scientifically via different in vitro and in vivo studies.

Molecular Characteristic of Dengue Virus against its Outbreak response of Red Sea State, Eastern Sudan - 2020

BACKGROUND: Dengue fever is ranked by the World Health Organization as the most critical mosquito-borne viral disease, globally. More than 40% of the world’s population, in more than 100 countries are at risk of dengue infection. AIM: The objective of this study was to determine the prevalence of dengue virus (DENV) genotypes and serotypes during disease outbreak 2020 in Port Sudan State, eastern Sudan. METHODS: This study was a descriptive cross-sectional study conducted at Eastern Sudan (Port Sudan state). Three hundred and eighty serum samples were collected from febrile patients including any individual aged ≥5 years old and excluded all patients suffering from Tuberculosis, rheumatoid arthritis was excluded and those who have a history of travailing to an endemic area within the past 2 weeks. Reverse transcription polymerase chain reaction (RT-PCR) assays were used to amplify a fragment of the viral polyprotein gene. The PCR products of the amplified viral polyprotein gene were purified, and partial sequences were generated and used to confirm the specificity of DENV sequences and to identify the virus serotype. Data analysis was performed using Statistical Package for Social Sciences (SPSS, version 23.0). RESULTS: Infection was confirmed in 27.9% in 106 samples out of 380 sampled sera, using DENVenzyme-linked immunoassay assay. The detection of DENV RNA was made possible using group-specific RT-PCR assay. The virus was DENV serotype 3 (DENV-3) serotype-specific RT-PCR assay. CONCLUSION: The findings of this study indicate that DENV-3 of DENV is circulating and we did not detected DEN-1, 2 and DEN-4 in outbreak in eastern Sudan during the year 2020.